Providing assistance to a mobile telephone subscriber travelling from a location to a desired location

ABSTRACT

A cellular telephone subscriber who wishes directory assistance services is connected in the conventional manner to an operator who identifies a destination telephone number desired by the subscriber. As in the prior art, the operator then initiates a call connecting the subscriber to the destination telephone number. However, rather than dropping all further involvement with the call, the preferred embodiment of the present invention continually monitors the connection thereby established for a predetermined DTMF signal issued by the customer, such as that obtained by pressing the &#34;*&#34; button. If such a signal is detected, the customer is transferred back to a directory assistance operator, who can then provide whatever further assistance is needed (e.g. redialing a busy number, or providing further directory assistance). Billing information for the calls originated by the directory assistance operator on the subscriber&#39;s behalf is logged in a database at the directory assistance center. This data is thereafter provided to the cellular carrier, permitting it to bill the subscriber for calls originated by the directory assistance operator.

This application is a continuation of application Ser. No. 08/527,437,filed on Sep. 13, 1995 which is a division of application Ser. No.08/234,644, filed Apr. 28, 1994.

FIELD OF THE INVENTION

The present invention relates to systems for providing directoryassistance services, and more particularly relates to the provision ofdirectory assistance services to cellular telephone subscribers.

BACKGROUND AND SUMMARY OF THE INVENTION

Telephone directory assistance services have been available for the pastcentury. While improvements have been made over the decades, suchsystems are still poorly suited for use by subscribers of cellulartelephone services.

In prior art directory assistance services, a customer dials an operatorand identifies the name and address of a party whose telephone number isdesired. The operator then locates the number, using printed directoriesor a computer database, and provides the number to the customer. (Theprovision of the number is sometimes done by the live operator, but moretypically is done with a computerized voice response unit that providesa synthesized voicing of the number.) After the customer's inquiry hasbeen satisfied, the connection to the operator is terminated.

While satisfactory for most customers, this arrangement is ill-suitedfor many cellular telephone customers. For one, such customers areusually away from their general work environments (e.g. in a vehicle),and thus may not have ready access to a pencil and paper in order tomake a note of the desired number. (Even if such materials areavailable, the customer may not find it convenient to interrupt otheractivities, e.g. driving, in order to make a note.) In addition, theprocess of initiating a second call--to the desired party--entailsfurther manual operations (e.g. hanging up, waiting for another dialtone, and dialing) which may be a hindrance to the customer's otheractivities.

The present assignee, in the prior art, has redressed certain of thesedifficulties by providing a directory assistance service that eliminatesthe need to make a note of the desired number, or undertake a redialingexercise. Instead, after determining the telephone number desired by thecustomer, rather than voicing it to the customer, the directoryassistance operator goes ahead and initiates a call to the desiredparty, and connects the new outgoing call to the original customer. (Theoperator may stay on the line as a conferenced party so as to providefurther assistance, or may withdraw from the connection, depending onthe particular implementation.) This arrangement obviates the need forthe customer to make a note of the voiced number, or to undertake aredialing exercise. However, if the initiated call is not completed(e.g. a "busy" tone is received), or if the customer desires furtherdirectory assistance, then the customer must again call the directoryassistance operator for help.

The problems associated with providing directory assistance services tocellular customers are not limited to hardships on the customers; thedirectory assistance service and the cellular carrier also confrontunique issues. In the assignee's prior art system, for example, thecellular carrier (which is typically responsible for billing of thecustomer) knows only that the customer has dialed the directoryassistance operator, but does not know the number to which the customeris ultimately connected by the operator. Billing is thereby complicated.In the prior art system, the toll charges (assuming toll calls arepermitted; often they are not) for the connection between the customerand the desired number are simply absorbed by the directory assistanceservice, and recouped by billing the cellular carrier a sufficientlylarge flat rate charge for each directory assistance call so as to coverthese costs. The cellular carrier then bills the subscriber a fixedamount for each directory assistance inquiry, regardless of the tollcharges of any further connection established for the customer by thedirectory assistance operator. This arrangement, however, has a numberof disadvantages. In addition to increased cost, it also fails toprovide the cellular carrier useful information about its customers'calling patterns, which may affect decisions relating to systemexpansion, etc.

In accordance with the preferred embodiment of the present invention, adirectory assistance service is provided which alleviates many of thesedrawbacks of the prior art. For example, in one embodiment, a customerwho wishes directory assistance services is connected in theconventional manner to an operator who determines the destinationtelephone number desired by the customer. As in the prior art, theoperator then initiates a call connecting the customer to thedestination telephone number. However, rather than dropping all furtherinvolvement with the call, this embodiment of the present inventioncontinually monitors the connection thereby established for apredetermined DTMF signal issued by the customer, such as that obtainedby pressing the "*" button. If such a signal is detected, the customeris transferred back to a directory assistance operator, who can thenprovide whatever further assistance is needed (e.g. redialing a busynumber, or providing further directory assistance). By this arrangement,the press of a single button by the customer summons further directoryassistance, rather than the redialing procedure required by the priorart.

The preferred embodiment further addresses the billing difficultiesassociated with completion of customer calls by directory assistanceoperators. According to this aspect of the preferred embodiment, thedirectory assistance service logs, in a billing database, informationidentifying the customer (i.e. the customer identification numberaccompanying the call from the cellular provider), the destinationnumber to which the customer is connected, and the date, time andduration of the customer/destination number connection. This log ofinformation is periodically provided to the cellular carrier, allowingit to bill the customer for the call connected by the directoryassistance operator and recoup the associated expense. This permits theflat rate charged by the directory assistance provider to be reducedcorrespondingly, and provides the cellular service with more detailedinformation about its customers' usage requirements.

The foregoing and additional features and advantages of the presentinvention will be more readily apparent from the following detaileddescription, which proceeds with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram depicting the hardware used to implement oneembodiment of the present invention.

FIG. 2 is a flow chart depicting the process by which directoryassistance is provided to a customer in accordance with the FIG. 1embodiment.

FIG. 3 is a flow chart depicting a mapping/locator service provided inthe directory assistance system of the FIG. 1 embodiment.

DETAILED DESCRIPTION

With reference to FIG. 1, a directory assistance center 10 according toa preferred embodiment of the present invention includes one or more T1links 12 for connection to customer networks, a private branch exchange(PBX) 14, and a channel bank 16 for coupling to a plurality of operatortelephones 18. Each operator is further equipped with a terminal 20 thatincludes a video display unit and a QWERTY keyboard with associateddialing pad. The operator terminals are coupled to a terminal server 22,which in turn is connected over a data network 24 to a database server26. The data network further connects to a PBX host computer 28 and avoice response unit (VRU) 30.

The T1 links 12 provide connection between the directory assistancecenter 10 and the cellular carrier's switching center, through whichincoming directory assistance calls are received. The T1 links 12further provide connection to the network over which outgoing calls areplaced (which network may be different than that used for incomingtraffic).

The PBX 14 is conventional, and its operation is governed byinstructions stored in the PBX host computer 28. These instructionssimply implement the processes hereafter described. In the preferredembodiment, the PBX supports digital T1 telephone circuits, while inother embodiments other PBXs can of course be used. Included in the PBXis digital signal processing circuitry which provides the requisiteconference capability (described below), and dual tone multi frequency(DTMF) and multi frequency (MF) tone generation/detection capabilities.

Incoming calls received by the PBX 14 are connected to an availableoperator via a T1 circuit 32 that is connected through the channel bank16 to an operator's telephone headset. If no operator is available whena call is received, the call is queued until an operator becomesavailable. The queuing and call distribution is standard Automatic CallDistribution (ACD).

The terminal server 22 simply serves as an interface between serialdevices, such as the operator terminals 20, and the data network 24,allowing the terminals to login as devices on the network.

The database server 26 provides operators with the means to search for acustomer's desired party, and determine the appropriate telephonenumber. In the preferred embodiment, the database provides thecapability to search not just by name and address, but also by type ofgoods/services and/or geographical region. (E.g. the preferred databasecan answer queries soliciting the names/numbers of shops carrying modelrocketry supplies in southeast Portland, Oregon, or of Chineserestaurants on a given street.) Data indexed in this fashion is usuallynot commercially available, so the present assignee starts with acommercially available database file (e.g. the Directory AssistanceDatabase Source available from U.S. West), and enriches it by addingfurther data manually.

Desirably, the results of the database search presented on theoperator's terminal 20 are not alphabetized prior to display, but ratherare presented in the order located by the database search engine. (Ifdesired, a deliberate randomization of order could be effected beforedisplay). Businesses at the beginning of the alphabet are thereby notunduly favored by customers using the directory assistance service.

The database software itself is conventional. The presently preferredbest mode us to use a relational database, such as is available fromSybase. However, much simpler software can alternatively be used, suchas DBase 4.

The voice response unit (VRU) 30 is incorporated into the system to playthe constantly repeated parts of an operator's speech, namely thevarious greetings and signoffs (or closings). Not only does this systemprovide a voice-saving and monotony-relief function for the operators,it performs a `branding` function (i.e. the pre-recorded messagesincorporate the name of the telephone company through which the customerwas routed to the directory assistance service), and it also reduces theamount of time an operator is actually connected to a customer.

The VRU 30 is connected via the data link 24 to the PBX host 28 (towhich it acts as a slave processor) and via one or more T1 spans to thePBX 14 itself. More than one VRU can exist in a system. At appropriatestages in a call progression, the PBX host 28 initiates a voice pathconnection between the VRU and the PBX such that the caller, or thecaller and the operator, are able to hear whatever pre-recorded speechis played on that circuit by the VRU. It then instructs the VRU, via thedata network, what type of message to play, passing data parameters thatenable the VRU to locate the message appropriate to the call state, theservice-providing telephone company, and the operator. The recordingdensity used is high enough to provide a good enough quality of messageplayback that most users of the system should be unaware they arelistening to a recording.

Method of Operation

Customers of a particular telephone company simply dial the accessdigits established for directory assistance by that company. Examples oftypical access digits are "*555" and "555-1212."

The participating telephone company's own switching system will thenreroute the call to the directory assistance service center 10 (via a T1channel), where it appears as an incoming call.

Automatic Call Distribution (ACD) logic is used to queue (if necessary)and distribute calls to operators in the order in which they arereceived, and such that the call traffic is distributed evenly among theoperators.

When a call is connected to an operator, the VRU 30 (also conferencedinto the call) plays a greeting message, using a message pre-recorded bythe connected operator. Both the operator and the calling customer hearthe message, which incorporates the name of the service or company towhich the customer is a subscriber (in other words, the call is"branded"). The message ends with a prompt, thus cuing the customer tovolunteer what information they are seeking.

When the automated greeting is complete, the VRU is disconnected, andthe operator and the customer are left connected by a 2-way speech path.From this point, the caller is interacting with a live operator.

In the event that the VRU is non-functional (for whatever reason), theincoming call is connected to the operator and a short "trill," or "zip"tone is played to indicate that a caller is on the line. (Note that onceoperators are logged in to the system, they wear headsets, and havetheir telephones 18 permanently off-hook. Their telephones do not ringwhen a call is presented). The operator then speaks a greeting andprompt in real time, instead of the VRU playing a message.

If the caller requests information concerning, for example, localtheater performances, the operator speaks a response based on hard copyinformation. At this point, the caller will be released from the call,and the operator becomes available to handle further calls.

If the caller is seeking directory assistance, the operator will engagein live dialogue to establish the name and other pertinent informationof the wanted party, and then initiate a database search using theoperator terminal 20 and associated database server 26. In the event ofan unsuccessful search, the operator will use alternative sources, suchas the Electronic White Pages (EWP) or even printed directories.

The operator can connect the caller to the wanted party's number usingone of two possible methods of call transfer: Blind Transfer or HotlineTransfer.

In either case, the call transfer is invoked by sending a sequence ofdigits (that includes the wanted party's number) to the PBX host 28. Theconventional method of doing this is simply dialing the digits on theoperator's telephone handset (having first depressed the "flash" key toobtain dial tone). This method is always available. A much quicker andmore accurate method is generally preferred: the operator highlights thedesired database entry on the screen of the terminal 20, and theninitiates Blind or Hotline transfer to that number by entering a fewkeystrokes on the terminal keyboard. In this case, the database server26 transmits the same digit sequence as part of a message to the PBXhost 28, via the network 24.

"Blind Transfer" is the normal means by which an operator establishes aconnection between the caller and the wanted party's number. As soon asthe PBX host 28 receives the Blind Transfer command (whether from thedatabase server 26 or the operator's telephone set 18), an attempt ismade to establish a route out of the PBX 14. If successful, the circuitis seized and the address digits propagated, using the protocol thecircuit is configured for: the operator is released from the call andmade available to receive further calls. If the VRU 30 is operational,it is commanded to play a signoff message (pre-recorded by thejust-released operator). If the VRU is not available, the operatorspeaks the signoff message before initiating the transfer. The VRUstatus is known by whether the call was initiated by a VRU-playedgreeting, or by zip tone. Failed routing attempts cause reorder tones tobe returned to the operator's handset, or an error indication to bereturned to the database server 26 (depending on how the PBX hostreceived the transfer command).

Like Blind Transfer, the "Hotline Transfer" method of establishing aconnection between the caller and the wanted party's number can beinitiated by the operator from either the telephone handset 18 or fromthe data terminal keyboard 20. The difference is that the operator isnot automatically released from the call in a Hotline Transfer. Instead,he/she is conferenced into the call by the PBX 28 and is able to monitorits progress. Using either the telephone handset or the data terminalkeyboard, the operator may withdraw from the call after verifying itsestablishment, or may cause the called circuit to be released and thenre-engage in dialogue with the caller.

Hotline Transfers are used when a caller requests that the operator"stay on the line."

If, after initiation of a transfer (whether or not it succeeds), and atany time before the caller hangs up, the caller requires furtheroperator assistance, the caller can perform a tone signal triggered,return transfer back to an operator (hereafter referred to as "tonetriggered return transfer") to an operator. This is done simply bypressing the "*" (star) key on the caller's telephone once or twice(depending on the system, and as instructed by the operator in thesignoff message).

The star tone(s) is detected by a DTMF receiver (allocated in the PBX 14for the entire duration of the call), and causes the caller to appear asa fresh call to the ACD logic. This in turn results in the caller beingconnected to an available operator, whereupon the PBX host 28 instructsthe connected VRU 30 to play the appropriate pre-recorded signoffmessage with return transfer instructions message. Note that theoperator to whom the call is connected is allocated according to the ACDalgorithm, and may or may not be the same operator that previouslyhandled this call. From this point, the call is treated in the same wayas a non-tone triggered return transfer call.

The "tone triggered return transfer" feature enables callers who havebeen transferred by means of a Blind Transfer to recall an operator ifthe transfer does not complete satisfactorily (for example, receipt ofreorder tone, busy tone, operator intercept tri-tones, ring-no-answer,silence, or wrong number). It also enables a caller to request afollow-on call at the completion of a successfully completed callwithout incurring the delay or difficulty of re-dialing into the system.

It will be recognized that, in the preferred embodiment, the desirednumber is not voiced to the customer unless explicitly requested.Sometimes a customer uses the "tone triggered return transfer" featureto request that the number be voiced if, for example, he finds afollow-up call is necessary later.

A flow diagram illustrating the sequence of events in a directoryassistance system employing the present the "tone triggered returntransfer" technique is provided in FIG. 2.

The "tone triggered return transfer" technique enables thecost-effective provision of many services not previously available.Referring to FIG. 3 for example, a directory assistance center may offermapping/locator services 50 which provide spoken directions to guidevehicle-based customers from their present location to a desireddestination. However, to obviate the need for the customer to write thedirections down while in the vehicle, the operator should be availableto issue instructions along the course of the vehicle's route. By usingthe "tone triggered return transfer" feature, the customer can receiveinitial instructions 54, and thereafter summon further instructions 58as needed along the route simply by pressing the star key 56. In such asystem, the customer's connection to the directory assistance center 52is maintained during the course of the trip, but the operator can attendto other customers while the travelling customer doesn't need theoperator's immediate attention. (Since tone triggered return transfermay return the customer to a different operator, provision is made fortransferring--with the customer--a pointer to the particular databaserecord (i.e. map or directions 53) being utilized by that customer, anda pointer to a current location within that record. By this arrangement,a different operator who is summoned for assistance using the "tonetriggered return transfer" feature 56 can pick up where the lastoperator left off 58.) While driving between operator instructions, thecustomer is simply kept in a "hold" state 55.

Billing issues

There are three billing components of a cellular-phone originated callto a directory assistance service according to the present invention:

1) "Air time," or the total time the caller uses the cellular carrier'scellular radio system to carry a call from his/her cellular telephone.This is the responsibility of the cellular carrier.

2) The per-call charge levied for use of the directory assistanceservice. This charge is made by the directory assistance service to thecellular carrier on the basis of the number of calls received from thecarrier in a particular time period.

3) Toll charge--the charge levied by a carrier for the duration of ananswered connection over a toll route originated by a directoryassistance operator. This charge is levied by the carrier used forcompletion of customer calls originated by the directory assistanceoperator. The cellular carrier is dependent on the directory assistanceservice to provide enough details of these calls to enable it toaccurately bill its subscribers accordingly. There are two ways of doingthis:

1) The directory assistance service provides "tickets" of all calls thatwere transferred and answered. The precise content and format of theticket is customer-defined, but includes at least the followinginformation: calling number, called number, date and time of connection(i.e. when answer indication was received), and duration of call. Theticket files can be transferred on magnetic tape or by means ofelectronic file transfer.

2) The digits that are dialed by the directory assistance service's PBXto initiate the call transfer (via the cellular carrier's network) canincorporate the calling party number ("A" Number Identification, orANI). The cellular carrier's own switching equipment then has all theinformation needed to generate the required tickets.

It is the cellular carrier's responsibility to rate the calls anddetermine what charge is to be levied.

Having described the principles of our invention with reference to apreferred embodiment and certain variations thereon, it should beapparent that these examples can be modified in arrangement and detailwithout departing from such principles. For example, while the inventionhas been illustrated with reference to a system in which a tonetriggered return transfer customer is routed back to the next availableoperator, in other embodiments, provision can be made for routing thecustomer back to the original operator. (In some systems, the customercan be given a choice: pressing one key for the first availableoperator, and another key to be inserted in the original operator'squeue.)

In view of the many possible embodiments to which the principles of ourinvention may be put, it should be recognized that the detailedembodiments are illustrative only and should not be taken as limitingthe scope of our invention. Rather, we claim as our invention all suchembodiments as may come within the scope and spirit of the followingclaims and equivalents thereto.

We claim:
 1. In a method of providing assistance to a mobile telephonesubscriber, the assistance taking the form of spoken directions to thesubscriber guiding the subscriber in travelling from a present locationof the subscriber to a desired location, an improvementcomprising:connecting the subscriber to a first human directoryassistance operator; determining a route from the present location tothe desired location; voicing to the subscriber directions correspondingto a first part of the route; placing the subscriber on hold; monitoringthe subscriber connection for a predetermined DTMF signal issued by thesubscriber; detecting said predetermined DTMF signal; reconnecting thesubscriber to a second human directory assistance operator, differentthan the first human directory assistance operator, upon said detectionof the DTMF signal; transferring to said second human directoryassistance operator a pointer to a database record established by thefirst human directory assistance operator, wherein said second operatorhas access to the database record accessed by the first human directoryassistance operator; and voicing to the subscriber directionscorresponding to a second part of the route; wherein the subscriber cansummon operator assistance as needed while travelling along the route.2. The method of claim 1 in which the reconnecting step comprisesreconnecting in response to detection of the predetermined DTMF signalfrom the subscriber only.
 3. The method of claim 1 in which themonitoring includes monitoring between initiation of the subscriberconnection and completion of the subscriber connection.
 4. The method ofclaim 1 in which the monitoring includes monitoring the subscriberconnection until the subscriber hangs up.
 5. The method of claim 1 inwhich the monitoring includes monitoring the subscriber connectionthroughout its duration.